رسائل ماجيستير
English
2015
Enhanced Propylene Production by Catalytic Cracking of Hydrotreated Vgo Over Novel Fcc Catalyst Additives
سليمان الخطاف, عبدالرحمن عز الدين حسن حسين
كلية الهندسة-جامعة الملك فهد للبترول والمعادن · السعودية
Fluid catalytic cracking (FCC) process is a source of considerable amounts of global propylene as well as gasoline. Its product distribution is increasingly shifting to maximize propylene yield in order to meet high demand from petrochemicals users.In this study, catalytic cracking of hydrotreated vacuum gas oil (VGO) was carried out in a microactivity test (MAT) unit. Commercial FCC USY catalyst (E-Cat) was used and modified by various zeolites with different pore structures and different Si/Al molar ratio. These zeolites included SSZ-74, SSZ-33, MCM-22, MCM-36, ZSM-5, TNU-9, IM-5, and ferrierite. At constant conversion and comparable Si/Al molar ratio, the highest propylene yield of ~11 wt.% was achieved over ferrierite and MCM-36 compared with 7 wt.% over E-Cat. An increase in light olefins yield over all additives was associated with a decrease in gasoline yield due to the cracking of gasoline-range reactive species. It was found that additives with lower ability to carry bimolecular reactions were more selective to light olefins. With increasing Si/Al molar ratio, both propylene and light olefins yields passed through maxima. Results of kinetic study showed that the additives helped to decrease activation energy for the cracking reaction of gasoline to gases.